Cog
Perception
What does it mean to recognize an object?
S → Primary sensation | recognition | | response selection → R
Percept → Concept Recognition
Categorization
How?
● As definitions
● As prototypes
● As exemplars
Definitions
List of necessary and sufficient properties
Chair = But:
- 4 legs
- Seat surface
- Backrest
Definitions
List of necessary and sufficient properties
bijv. What is a male?
- of, relating to, or being the sex that typically has the capacity to produce relatively
small, usually motile gametes which fertilize the eggs of a female
- having a gender identity that is the opposite of female
Or according to the IAAF: a person with at least five nmol/L testosterone in
the blood → according to IAAF is this woman athlete not a female, too
much testosterone in her blood
,Male vs female in the brain
● But do definitions mean anything when we view a male or female?
● Neurons in the inferior temporal cortex can distinguish male and female faces
● Study by Afraz et al. (2015)
→ study with people looking at faces and pointing them to the female or male side: photos on
top are most likely male/female, more downwards these faces become (more) universal
Prototype
● Prototype = central representation of a category: the “average”, or “center of gravity”
of all earlier experienced objects of that category.
● Graded representation: Membership of an object to a category depends on the
similarity (distance) to the prototype.
→ circled object the ‘prototype’, how further away
how lower the graded representation
1. Method: Rating scale.
Participants rate the typicality of a certain example for a category.
2. Method: Sentence verification: “apple is a fruit” (true/ false) → Smith et al. (1974)
, 3. Method: Priming in same/different judgment
Memory is drawn towards prototype
Bartlett’s (1932) drawing experiments:
→ people draw from what they know,
weird looking owl to a cat
4. Schemata: General knowledge about situations, e.g.
- Kitchen
- Museum
- University office
30% of participants claimed there were books in the room.
(Brewer & Treyens, 1981)
5. Scripts: General knowledge about a sequence of events
- Make tea
- Take a metro
- Buy a bread
- How to rob a bank
, What is being stored?
Idea of a prototype is attractive:
● Concepts are intrinsically ”fuzzy” – they have no fixed boundaries, like human
categorization.
● Explains findings of typicality (rating, RT, priming, naming, etc.)
But what is stored?
● The prototype, abstracted from earlier experiences?
OR
● Exemplars: representation of each actual experience
Prototype vs. Exemplar approach
Dogs that we experience We store everything
Prototype approach
● Advantage: very efficient storage
● Disadvantages:
- requires separate storage of unique exemplars, e.g. “my dog Bella”. (So how
do you know Bella is a dog?)
Exemplar approach
● Disadvantage: a lot of capacity required for storage.
● Advantages:
- unique exemplars are stored as any other exemplar - no categorization
problem
Organization of semantic memory
Semantic memory seems to be structured
● One fact triggers the retrieval of related facts (Australia +
capital = Canberra)
● Mistakes are often near-misses (e.g. Melbourne, Sydney)
What is the structure of semantic memory like?
● Parallel distributed processing
● Multiple-trace theory (in addition to the book)
● Semantic network: the hierarchical model
Perception
What does it mean to recognize an object?
S → Primary sensation | recognition | | response selection → R
Percept → Concept Recognition
Categorization
How?
● As definitions
● As prototypes
● As exemplars
Definitions
List of necessary and sufficient properties
Chair = But:
- 4 legs
- Seat surface
- Backrest
Definitions
List of necessary and sufficient properties
bijv. What is a male?
- of, relating to, or being the sex that typically has the capacity to produce relatively
small, usually motile gametes which fertilize the eggs of a female
- having a gender identity that is the opposite of female
Or according to the IAAF: a person with at least five nmol/L testosterone in
the blood → according to IAAF is this woman athlete not a female, too
much testosterone in her blood
,Male vs female in the brain
● But do definitions mean anything when we view a male or female?
● Neurons in the inferior temporal cortex can distinguish male and female faces
● Study by Afraz et al. (2015)
→ study with people looking at faces and pointing them to the female or male side: photos on
top are most likely male/female, more downwards these faces become (more) universal
Prototype
● Prototype = central representation of a category: the “average”, or “center of gravity”
of all earlier experienced objects of that category.
● Graded representation: Membership of an object to a category depends on the
similarity (distance) to the prototype.
→ circled object the ‘prototype’, how further away
how lower the graded representation
1. Method: Rating scale.
Participants rate the typicality of a certain example for a category.
2. Method: Sentence verification: “apple is a fruit” (true/ false) → Smith et al. (1974)
, 3. Method: Priming in same/different judgment
Memory is drawn towards prototype
Bartlett’s (1932) drawing experiments:
→ people draw from what they know,
weird looking owl to a cat
4. Schemata: General knowledge about situations, e.g.
- Kitchen
- Museum
- University office
30% of participants claimed there were books in the room.
(Brewer & Treyens, 1981)
5. Scripts: General knowledge about a sequence of events
- Make tea
- Take a metro
- Buy a bread
- How to rob a bank
, What is being stored?
Idea of a prototype is attractive:
● Concepts are intrinsically ”fuzzy” – they have no fixed boundaries, like human
categorization.
● Explains findings of typicality (rating, RT, priming, naming, etc.)
But what is stored?
● The prototype, abstracted from earlier experiences?
OR
● Exemplars: representation of each actual experience
Prototype vs. Exemplar approach
Dogs that we experience We store everything
Prototype approach
● Advantage: very efficient storage
● Disadvantages:
- requires separate storage of unique exemplars, e.g. “my dog Bella”. (So how
do you know Bella is a dog?)
Exemplar approach
● Disadvantage: a lot of capacity required for storage.
● Advantages:
- unique exemplars are stored as any other exemplar - no categorization
problem
Organization of semantic memory
Semantic memory seems to be structured
● One fact triggers the retrieval of related facts (Australia +
capital = Canberra)
● Mistakes are often near-misses (e.g. Melbourne, Sydney)
What is the structure of semantic memory like?
● Parallel distributed processing
● Multiple-trace theory (in addition to the book)
● Semantic network: the hierarchical model
